std::tuple_size(std::array)

 

C++

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operator==operator!=operator<operator>operator<=operator>=operator<=> (until C++20)(until C++20)(until C++20)(until C++20)(until C++20)(C++20)

Helper classes

tuple_size

tuple_element

Deduction guides(C++17)

 

Defined in header <array>
template< class T, std::size_t N > struct tuple_size< std::array<T, N> > :     std::integral_constant<std::size_t, N> { };		(since C++11)

Provides access to the number of elements in an std::array as a compile-time constant expression.

Inherited from std::integral_constant

Member constants

value [static]

N, the number of elements in the array (public static member constant)

Member functions

operator std::size_t	converts the object to std::size_t, returns value (public member function)
operator() (C++14)	returns value (public member function)

Member types

Type	Definition
value_type	std::size_t
type	std::integral_constant<std::size_t, value>

Example

Run this code

#include <iostream>
#include <array>
 
template<class T>
void test(T)
{
    int a[std::tuple_size<T>::value]; // can be used at compile time
    std::cout << std::size(a) << '\n';
}
 
int main()
{
    std::array<float, 3> arr;
    test(arr);
}

Output:

3

See also

Structured binding (C++17)	binds the specified names to sub-objects or tuple elements of the initializer
std::tuple_size<std::tuple> (C++11)	obtains the size of tuple at compile time (class template specialization)